Electric vehicles have always been of high interest in the field of low environmental impact mobility. The poor diffusion of these vehicles is substantially due to two factors: their limited autonomy (maximum values in the range between 100 and 200 km); and the battery recharging time (typically in the range from a few dozens of minutes to several hours).
Furthermore, the batteries have relatively large volumes and heavy weights and provide a much lower energy density than the current automotive chemical fuels.
In order to solve these drawbacks, it has been suggested to create an appropriate, fixed infrastructure capable of supplying electricity, which is picked up by the vehicle by means of appropriate conductive elements pressed against the ground. Thereby, the batteries are exclusively used on road stretches free from such an infrastructure. Vehicle autonomy becomes substantially unlimited, and the battery recharging times are null (because the batteries are recharged while travelling).
Obviously, when including a ground surface infrastructure is desired, instead of an overhead infrastructure (such as trolley bus power supply lines), the risks of electrocution of people who may occasionally come in contact with the ground infrastructure must be avoided.
In order to solve such a problem, ground power supply lines comprise a series of conductive segments, which are aligned along the vehicle route and are electrically isolated from one another: upon the vehicle passing, only one of the segments which is underneath the vehicle is live, in response to a command emitted by the vehicle itself, to pick up the electric current.
U.S. Pat. No. 6,230,861 describes an electric traction vehicle provided with two longitudinally aligned brushes, one for picking up the live electricity and the other for closing the electric circuit. The conductive segments are associated with respective switching circuits, controlled by the vehicle to connect each segment to a live line and to a ground line, when either the aforesaid brushes come in contact with such a segment.
The switching circuits, the live line and the ground line are buried, whereby this solutions requires long implementation times and high costs, in particular for excavating.
Moreover, the road lane where the electric power line is installed is reserved only to electric vehicles intended to pick up the electric current, i.e. it may not be used by all motor vehicles circulating on the road, especially because the conductive segments are carried by an insulating frame which protrudes from the top of the road surface.
At the same time, the wear caused by the sliding contact between the brushes and the conductive segments is relatively high, whereby the brushes need to be frequently replaced.